探讨应用三维水晶反转仿真成像技术（3D-ICRV）分析正常胎儿脑沟和脑回发育变化规律的方法。

选取2019年1月至2021年12月于南方医科大学第一临床医学院附属深圳妇幼保健院进行产前检查的正常孕周连续的单胎妊娠孕妇，连续孕周段为15~35孕周，使用经腹超声以丘脑横切面获取三维容积。采用一种全新的3D-ICRV超声技术，对胎儿大脑半球的脑沟回进行大脑表面3D-ICRV成像，选取其中能够清晰显示胎儿脑表面沟回的容积，观察并描述胎儿大脑表面脑沟脑回的发育变化规律。所有病例均进行了产后随访。

300例正常连续孕周的单胎胎儿纳入研究。成功获取颅脑容积及清晰的3D-ICRV图像的胎儿共294例，成功率为98%（294/300）。每例胎儿选取2个最佳的颅脑容积，共计588个颅脑容积进行分析。脑沟回在3D-ICRV成像上呈现一种相对恒定的变化发育规律，在妊娠15~25周，外侧裂是第一个也是唯一能在3D-ICRV图像上被识别的结构。从26~35孕周，除大脑外侧裂发生变化外，脑表面的沟、回相继出现，并逐渐加深。其中，在26周最先出现中央沟及颞上沟，然后依次出现额上沟、顶内沟、额下沟、颞下沟等。25~30孕周是大多数脑沟回显现的主要时期，是评价皮质发育的最佳时期。

应用3D-ICRV成像可以显示正常胎儿脑沟回发育变化规律，了解这些变化对产前评估大脑皮层发育成熟度及进一步的临床咨询和管理具有重要意义。

To explore sulcus and gyrus alterations on normal fetal brain surface using three-dimensional inverse crystal and realistic vue (3D-ICRV) technique.

This is an retrospective study in which we retrospectively reviewed the 3D volume images of the normal fetal brain (15 to 35 gestational weeks) collected from January 2019 to December 2021 at Shenzhen Maternity and Child Healthcare Hospital Affiliated to Nanfang Medical University. 3D volume images were acquired in the transthalamic or transventricular plane on transabdominal ultrasonography and post-processed by 3D-ICRV. Volume images that were able to demonstrate the primary sulci and gyri on fetal brain surface clearly were selected. The morphology of the sulcus and gyrus and the alteration of apical angle on the Sylvian fissure were recorded according to the order of gestational weeks. Postnatal follow-up was performed in all cases.

During the study period, 300 ultrasound examinations were reviewed, and 588 3D volume images from 294 fetuses (n=294; median gestational weeks, 26.93; median maternal age, 31.22 years) were qualified. The Sylvian fissure was the first structure recognized between 15 to 25 gestational weeks. From 26 to 35 gestational weeks, the primary sulci and gyri emerged gradually. At 26 weeks, the central sulcus and superior temporal sulcus appear first, and then the superior frontal sulcus, intraparietal sulcus, inferior frontal sulcus and inferior temporal sulcus appear successively. Gestational weeks of 25 to 30 was the best time window to visualize the primary sulcus and gyrus on brain surface. Follow-up showed no abnormality.

Fetal brain surface configuration can be visualized through 3D-ICRV. Understanding these changes is of great significance in evaluating the maturity of cerebral cortex development as well as prenatal consultation and further examination for clinical management.